This invention relates to a device that can automatically thread an eye of a needle on a sewing machine.
Threading the needle of a sewing machine is a troublesome operation. To facilitate threading, various threading devices are proposed, for example, in Japan Published Unexamined Patent Application Nos. S63-46197 and H1-113092, in which a spring exerts an upward force on an actuating rod. The actuating rod is lowered manually or automatically through an air cylinder. A threading rod interlocks with the actuating rod, lowers, and further rotates. A threading hook thus extends through a needle eye and catches the thread. Subsequently, when the threading hook leaves the needle eye, one end of the thread is drawn into and through the needle eye.
However, in the related-art references, if an operator by mistake lowers a manual threading lever or presses a threading switch during sewing operation, a threading rod rotates. The threading hook moves toward the needle, which is vertically moving according to the operation of a sewing-machine motor, and may break upon contact with the needle. To avoid such malfunction, the manual threading lever and the threading switch are provided on the upper left side, under the face plate, or in another position of the sewing machine that the operator must take care to locate or cannot easily access.